A promising alternative treatment technology for accomplishing the destruction and detoxification of organic hazardous chemicals for on-site remediation of ground water is fixed-growth biological treatment engineered to optimize the performance of the white rot fungus Phanerochaete chrysosporium. P. chrysosporium has been shown to degrade various contaminants in laboratory shake cultures. In addition fixed-growth processes have been shown to considerably increase the lignin peroxidase activity that is presumed to be responsible for the degradation process. The proposed research approach is to use a contained fixed-growth fungal reactor (FGFR) treatment process at the bench and pilot scales to detoxify simulated and actual ground waters by degradation and mineralization of polycyclic aromatic hydrocarbons and pentachlorophenol at environmentally important concentrations. The proposed goal is to mineralize these contaminants to CO2 and H2O, thereby supporting the major emphasis of the Superfund Amendments and Reauthorization Act of 1986 (SARA) concerning treatment technologies that offer permanent protection of human health and the environment. Information concerning the technical feasibility, engineering optimization, design, field scale operation aspects, and cost effectiveness of the fixed-growth biological reactor using P. chrysosporium for degradation and detoxification of hazardous chemicals in ground water will be generated as a result of the proposed scope of work.